1. Field of the Invention
The present invention relates generally to earth boring devices and, more particularly, to an adjustable earth boring device which provides a strong, easy to use, adjustable mount for cutters on the device.
2. Description of the Prior Art
Earth boring devices have been in use for years for such applications as well drilling and the like. Typically, earth boring devices fall within the categories of rock bits, hole openers, and reamers. Such earth boring devices are usually made in segments and then welded together. Alternatively, in the utility horizontal boring industry, hole openers or reamers are usually made from segments of cut down tri-cone rock bits. Segments from the cut down bits are then mounted on a shaft or body that has proper box or pin connections. The boring devices so mounted are positioned so as to define a desired hole diameter and usually welded securely in place on the body.
Osadchuk, in U.S. Pat. No. 5,979,574, described a horizontal boring device having wedge shaped pockets and segments to allow removable cutting segments to be used. Unfortunately, the segments are pinned to a predetermined position on an axial member, and are not adjustable to permit boring holes of a desired different diameter. On the other hand, some oil field reamers use an adjustable wedging device and plate shims to adjust gage diameter to compensate for wear.
One problem with conventional earth boring devices is that most such devices are designed and built to bore only one size hole. Further, repair and replacement of components on such devices is very difficult due to their being welded together from segments. On the other hand, those products that are designed to be adjustable are weak or cumbersome to work with.
While these devices may be suitable for the particular purpose for which they are designed, they do not provide a strong, easy to use, adjustable mount for cutters on earth boring devices. In these respects, the adjustable earth boring device according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of providing a strong, easy to use, adjustable mount for cutters on earth boring devices.
The present invention provides a new adjustable earth boring device construction which provides a strong, easy to use, adjustable mount for cutters on earth boring devices. In a first preferred embodiment, the boring device of the present invention generally comprises a grooved wedge shaped pocket and a matching cutter segment with means to secure the cutter segment in the pocket. The wedge shaped pocket in the boring head is axially aligned with the boring device. Each side of the pocket has deep grooves somewhat resembling bolt threads. There may be provided a slot in the rear of the pocket for a bolt that secures the segment tightly in place. Further, there may be provided additional threaded holes in the bottom of the pocket for a back up securing means.
In another preferred embodiment, the pocket is not wedge shaped, but rather defines parallel axial grooved side walls. Vertical, i.e. substantially radial installation grooves cut across the axial grooves to permit easy installation and removal of the removable segment. Retaining wedges are then provided to retain the segment in place.
The cutter segment has a rolling cone cutter or series of blades or picks for cutting earth formations on the head end and a wedge shaped mounting body supporting it. The mounting body of the cutter segment has grooves that mate with the pocket grooves. The grooves are constructed such that the segments can be mounted at differing heights from the centerline of the boring head, thus determining the diameter which the boring device will cut. The back end of the segment has a threaded hole for the securing bolt that locks the segment into the pocket. There are bolt holes through the segment for a secondary securing device. The main locking device is a bolt that goes through the slot in the back of the pocket and into the rear of the segment. When tightened, it pulls the segment very securely into the pocket. After the segment is locked into place, additional bolts through segment and into holes in the bottom of the pocket provide a secondary or safety lock.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.
A primary object of the present invention is to provide a adjustable earth boring device that will overcome the shortcomings of the prior art devices.
An object of the present invention is to provide a adjustable earth boring device for providing a strong, easy to use adjustable mount for cutters on earth boring devices.
Another object is to provide a adjustable earth boring device that can be easily adjusted to bore differing hole sizes in earth formations.
Another object is to provide a adjustable earth boring device that allows differing types of boring cutters to be easily exchanged on the same boring head.
Another object is to provide a adjustable earth boring device that allows easy field replacement of damaged cutters on earth boring devices.
Another object is to provide a adjustable earth boring device that holds boring cutters very securely on the boring head and still allows them to be adjusted or replaced easily.
Other objects and advantages of the present invention will become obvious to the reader and it is intended that these objects and advantages are within the scope of the present invention.
To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated.